The invention is concerned with cooking food products, especially on a commercial basis. More specifically the invention is concerned with a belt grill or belt cooking apparatus, with improved structure enabling the formation of grill stripes or patterns in the food product while it is being cooked in the belt grill.
Belt cooking devices known as belt grills have been known and used, particularly for commercial cooking of products such as hamburgers, sausage patties, chicken and fish filets, steaks, chops, french toast, cheese sandwiches, pancakes and other food products. Cooking is effected by heat conduction to both sides of the food product, the heat being conducted through moving belts with heated platens behind them. A belt grill device is disclosed in Norris U. S. Pat. No. 3,646,880.
In general, a belt grill comprises upper and lower heated platens arranged in generally parallel planes, with two opposed belts of flexible heat resistant and heat conducting material conveyed in contact with the hot platens. The belts typically have been Teflon laminated over a fiberglass fabric. The product is placed on the lower Teflon belt at an entry end, and is sandwiched between the upper and lower conveyor belts as it advances, with both belts moving at the same speed. As the food product progresses, it is engaged with some pressure between the belts, each belt being backed up by a hot plate which conducts heat through the belt into the item being cooked.
In such belt grills, generally the upper platen and belt can be raised and lowered to accommodate various thicknesses of products to be cooked. Further, the separation between the belts and platens may be set to vary along the product path, becoming narrower toward the outlet end to accommodate shrinkage of food products during cooking.
The platens as well as the belts on such known belt grills have smooth and regular surfaces, so that the food products are engaged by and travel between generally planar surfaces.
In the case of certain food products it is desirable to have grill marks or grill stripes on the cooked product, to enhance the appearance of the product to the consumer. Such products include hamburger, pork, chicken patties, ham, beef, lamb, steaks, chops, fish and chicken filets and some sandwiches. Conventional belt grills are intended to establish uniform cooking of a product, and do not have any provision for the formation of grill marks in the surfaces of products.
Wallick et al. Pat. No. 4,373,431 disclosed a wiener cooking conveyor device having a heated grill which contacts the wieners as the wieners move in a conveyed path. The wieners rotated through one revolution as they were rolled against the heated grill, so as to form circumferential grill stripes around the tubular wieners. The disclosed device in the Wallick et al. patent did not utilize or have any relationship to a belt cooking device as described above.
U. S. Pat. Nos. 4,089,260 (Brown and Forney), 4,297,942 (Benson et al.) and 4,433,621 (Van Wyk et al.) disclosed various other arrangements for forming browning, searing or grill marks on meat products as the products are moved by conveyor means. These have involved either hot gases contacting the surfaces of the meat products, heated metal brands or bars, or both. None involved or contemplated the principles of the present invention described below.